Yes, seals compatibility for the same transmission design over different model years could be (or could be not) an issue. Similar situation with Toyota A750F AT, when it was introduced it had T-IV for one(?) year before they changed seals to make it as durable with WS fluid - this has been a subject to some confusion in Toyota community. Very similar if not exactly the same as with what user nascarnation mentions on Dex VI front. A 'wrong' fluid may work for a long time, but the 'correct' one will work longer.
if on top of that we have not exactly the same units on line, this could be even more fun. Especially in locales where people expect to use their vehicles much longer.
if on top of that we have not exactly the same units on line, this could be even more fun. Especially in locales where people expect to use their vehicles much longer.